Back in 2015, NASA posted a job announcement: "ASTRONAUTS WANTED." The legendary U.S. space agency does this every two years — how else would they get new astronauts? — but this time a record-breaking number of applicants poured in, as 18,353 hopefuls vied for 12 coveted positions.

The selection process is extremely rigorous — NASA has only employed 338 astronauts in its 58-year history — but the new crop of space-bound humans come from diverse academic backgrounds: they have degrees in everything from nuclear engineering, to astronautics (the study and practice of navigating beyond the earth's atmosphere) to marine biology, to emergency room medicine. Five women and seven men make up this class of new recruits, making it the largest incoming group of astronauts NASA's brought on since 2000.

Of course, just because they've been selected for the job doesn't mean they're blasting off to space tomorrow. As difficult as it is to get hired as a NASA astronaut, the two-year training and evaluation process is arduous. Before they're allowed to enter the final frontier, the candidates (known internally at NASA as "ascans") will have to learn the types of things you'd expect — how to operate every single do-dad on the International Space Station, for instance — but they will also have to learn to speak Russian and how to fly a T-38 jet.

But though the candidates have their work cut out for them starting in August when they report for duty, they're not going to let a grueling training schedule get in the way of being people. Jessica Watkins, for instance, studies landslides on Mars, but she also loves rugby, skiing, rock climbing and creative writing. At just 29 years old, she's the youngest of the group. Zena Cardman can probably answer all your questions about microbial communities living around deep water hydrothermal vents, but she's also interested in raising chickens and glider flying. Jonny Kim will be bringing his experience as an emergency room resident physician and Army Special Forces vet Dr. Frank Rubio, will be spending quite a bit of time away from his four children. He's 41 years old, the second-oldest of the new batch, and one of six candidates with a military background.

Current astronauts welcome the new recruits in this NASA video:

Now That's Interesting

The crush of more than 18,000 applicants more than doubled the long-standing record of 8,000 hopefuls who applied in 1978.